Re: Job coverage for contaminated filters

[avest@magnus.acs.ohio-state.edu (Albert Lee Vest)]

>hypothetical problem.
>
>Provide contamination control for changing filters on an air handling system
>which tends to build up Be-7 in the filters.
...., a
>cooling coil, and back out into the space.
>
>Now for the fun part - the air handler is ~ 60' up in the air at the top of
>a dome shaped "hall".  There is no catwalk.  An aerial "manlift" is used to
>access the area (it sways a lot).
>
>(the main hazard of the job is the aerial lift)

Since it's hypothetical, how about designing the filter bank (or even the
whole air handler) to be raised and lowered on the "manlift", *instead of*
the (wo)man?  The worker can change the filters at ground level with no
(well, at most very little) risk of falling.

>Lastly, how do I check people and items for Be-7 contamination at the
>rediculously low limit of 1000dpm/100cm^2  IN THE FIELD.  (a pancake GM sees
>this nuclide at around 100 cpm per 15,000 dpm)

Since the filter is as you describe, any Be-7 found would be in the form of
particulates, rather than evenly-spread contamination.  If 1000dpm/100cm^2
is "rediculously low", it should be easy to show that the additional risk
associated with missing (and not decontaminating) several 15,000 dpm (Be-7)
specks of dust is small enough to be negligible, and including that in your
license application as justification for using a field frisking threshold of
15k dpm (or even more) instead of 1k.

>Did I mention, this is just a hypothetical case?

Did I mention I'm not an expert?

Albert Lee Vest           The Ohio State University
Health Physicist    Room 103 1314 Kinnear Road Bldg
(614)292-1284                     1314 Kinnear Road
avest@magnus.acs.ohio-state.edu   Columbus OH 43212
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